This invention relates to an apparatus, systems and methods for plugging a pipe under pressure, and is particularly applicable for plugging a pipe, or pipeline having therein high temperature liquids or gases. “Pipe” as used hereinafter is inclusive of any tubular member made of metal for carrying fluid (liquid or gas).
Machines for tapping an opening in a pipe are well-known. Prior issued U.S. patents for tapping machines include U.S. Pat. No. 3,614,252 entitled TAPPING APPARATUS; U.S. Pat. No. 4,579,484 entitled UNDER WATER TAPPING MACHINE; U.S. Pat. No. 4,880,028 entitled COMPLETION MACHINES; U.S. Pat. No. 5,439,331 entitled HIGH PRESSURE TAPPING APPARATUS; U.S. Pat. No. 5,612,499 entitled METHOD OF INSERTING A SENSOR INTO A PIPELINE and U.S. Pat. No. 6,012,878 entitled PRESSURE BALANCED SUBSEA TAPPING MACHINE.
Tapping machines, such as the kind described in the above-mentioned U.S. patents, are for tapping a hole in a pipe while liquids or gases are flowing through them—that is, while the pipe is under pressure. Tapping procedures of this type are customarily carried out primarily for one of two purposes—that is, to provide a branch fitting on the pipe or to enable fluid flow through the pipe to be blocked. Other examples of prior art that describe and illustrate plugging the interior of a pipe usually associated with first tapping the pipe, include the following United States patents:
PATENT NO.INVENTORTITLE3,599,663FreemanHot Tapping Apparatus3,626,475HicksHigh Temperature Pipe-Plugging Apparatus3,665,966Ver NooyPipe Plugger3,872,880Ver Nooy et al.Plugging Apparatus4,411,459Ver NooyBranch Fitting forProviding Access to theInterior of a Pipe5,443,095Glossop, Jr.Fluid Blocking Device5,531,250Freeman et al.Device for Plugging theInterior of a Pipe
Tapping a pipe normally involves the use of a circular saw, examples of which are illustrated and described in the following United States patents:
PATENT NO.INVENTORTITLE5,360,300SullivanCutter Shell5,451,128HattersleyCutter Tool HavingRemovable Teeth5,466,099Sullivan et al.Cutter Shell for FormingHoles of ImprovedCylindricality
Devices for plugging a pipe that has been tapped are also well-known as illustrated by U.S. Pat. No. 5,531,250 entitled DEVICE FOR PLUGGING THE INTERIOR OF A PIPE.
These patents are incorporated herein by reference since they provide a thorough background relating to the subject matter of the present invention.